/Engine/Source/Runtime/RenderCore/Public/ShaderPipelineCache.h
Saves the current shader pipeline cache to disk using one of the defined save modes, Fast uses an incremental approach whereas Slow will consolidate all data into the file.
static bool SavePipelineFileCache ( [FPipelineFileCacheManager::SaveMode](API\Runtime\RHI\FPipelineFileCacheManager\SaveMode) Mode )